The use of X-ray systems for baggage and parcel inspection in order to detect contraband has increased considerably in recent years because of terroristic activity which exists at present throughout the world. It is essential that such X-ray inspection equipment be easy to operate, be capable of providing immediate results, and that such equipment does not create any external radiation which could result in X-ray exposure to persons in the vicinity of the equipment.
The X-ray inspection unit of the present invention fulfills all the criteria set forth above. The apparatus of the invention is of the type which finds particular utility in the detection of contraband, and it is intended to be used by governmental, or other agencies, for the inspection of mail, parcels, baggage, and the like, in order to detect weapons, bombs, or other explosives, before the parcels are distributed and opened. One particular use for the apparatus of the invention is in the examination of parcels and food supplies entering a prison. However, it will become evident as the description proceeds, that the apparatus of the invention is of the type having general utility, not only in prisons, but in courtrooms, mailrooms, airports, nuclear sites, and the like.
The X-ray inspection apparatus of the present invention, unlike the prior art X-ray inspection apparatus, is of a modular construction, in that it includes a first lead-shielded modular unit which contains the X-ray viewing screen, mirror, viewing port, inspection compartment and access door; and a second lead-shielded modular unit which contains the X-ray generator. As explained briefly above, the modular units are prefabricated, and they are inserted into a metal cabinet, the cabinet being composed, for example, of steel, or other appropriate material which need not be shielded for X-rays.
One of the advantages of the modular design of the X-ray inspection apparatus of the present invention is that a substantial weight reduction may be achieved, as compared with prior art apparatus of the same general type in which the entire cabinet is shielded for X-rays. For example, in a constructed embodiment of the invention, a weight reduction of 300 pounds has been realized, as contrasted with typical prior art apparatus of comparable power levels. This substantial weight reduction is realized because the lead shielding is used only for the internal modular units, and the cabinet itself need not be shielded.
The modular construction of the apparatus of the invention not only permits a substantial weight reduction, but also permits the cabinet to be constructed to have a clean and attractive appearance, as compared with the bulky machines of the prior art. The substantial weight reduction also provides a considerable saving in shipping costs.
The modular design of the X-ray inspection apparatus of the present invention also obviates any need for access doors in the cabinet, which access doors must be electrically interlocked with the X-ray generator to prevent X-ray exposure when opened, and which interlocks are subject to failure. It is usual for the prior art machines to include at least two such access doors.
Another advantage of the X-ray inspection apparatus of the present invention is that the viewing mirror and fluorescent X-ray viewing screen are contained in a sealed chamber within the first modular unit, and are never exposed to air or dust after the unit has been completed and closed.
As mentioned above, the X-ray generator in the apparatus of the invention is mounted in the second modular unit in the lower portion of the cabinet, and it is readily accessible for removal for maintenance purposes. The removal of the X-ray generator unit from the cabinet is achieved through a removable panel in the cabinet, and there is no need to disturb the unit in any way. Since the X-ray generator itself is enclosed in the second unit, there is no need for the access panel to be shielded, and no need to interlock the panel with the X-ray equipment.
The X-ray inspection apparatus of the invention, in the embodiment to be described, includes a hooded viewing port which is mounted on the front panel of the first modular unit, and through which the fluorescent X-ray viewing screen can be observed, by means of the mirror which is also mounted within the first modular unit. The hood may be removable to permit photographs of the image of the screen to be taken through the viewing port, if so desired.